Pushing pyyaml to 6.0.1 to resolve compat with Python 3.12

[ravindk89]

yaml/pyyaml#736

Python 3.12+ is somewhat broken when trying to install fresh.

Bumping PyYaml to 6.0.1 seems to fix it. There are some warnings that we might have to freeze at Python 3.12 until PyYaml updates to fully support it at some indeterminate time in the future.

@djwfyi @feorlen please test w/ a clean venv (e.g. python -m venv testvenv or something) and make sure that you can still pip install -r requirements.txt and build w/ PyYaml 6.0.1

[feorlen]

Will try later today. Wondering if this is related to my recent problem on macOS. I was trying to nuke and pave with fresh 3.12.

[djwfyi]

Successfully built Linux and K8s with 6.0.1 on macOS.

[feorlen]

I was also successful on macOS, after reinstalling py 3.12.3 and pip.

I get this warning on both linux and k8s:

(node:67067) [DEP0180] DeprecationWarning: fs.Stats constructor is deprecated.
(Use `node --trace-deprecation ...` to show where the warning was created)

and this on k8s

Browserslist: caniuse-lite is outdated. Please run:
  npx browserslist@latest --update-db
  Why you should do it regularly: https://github.com/browserslist/browserslist#browsers-data-updating

Running the npx command says No target browser changes but after that I no longer get that warning on k8s.

[ravindk89]

The node stuff might require some fixups in kes-docs-theme, but are noncritical for our purposes.

Will merge this up